1. Field
This invention relates generally to tubular connectors. It is specifically directed to rotatable joint structures which provide a sealed passageway between the interiors of discrete components of a fluid-containing assembly. A representative such joint structure is embodied as a connector at the interface between an intubation patient fixture and an endotracheal catheter assembly.
2. State of the Art
There are a variety of circumstances in which it is necessary or desirable to provide a flow or other travel path through the interiors of adjacent components of a fluid-containing assembly of discrete components. When the individual components of such an assembly are subjected to mechanical forces tending to rotate one component with respect to another, it is often essential to provide that travel path through a joint structure which permits rotating or swiveling movement. In many cases, the cost constraints imposed by a given application impose a practical limitation on the permissible expense of any joint structure included within the system.
As an example, closed systems for endotracheal suctioning and ventilating typically include a manifold enabling introduction of ventilating gases and intermittent exhalation of patient breath simultaneously with insertion and operation of a tracheal suctioning catheter. The manifold structure typically includes multiple ports, usually the open ends of respective conduits extending from a common chamber. One such port is interfaced to a patient through a patient connection device. The suction catheter is often included within an assembly which is connectable to a second port of the manifold. The catheter assembly conventionally includes a collapsible plastic envelope positioned entirely to surround the catheter. A practitioner manually externally collapses the envelope onto the external surface of the catheter, and advances the catheter through the manifold into an access tube connected to a patient, retracting the catheter in a similar fashion following the aspiration procedure.
Manipulations, or other disturbances, of the catheter assembly tend to cause irritation to the patient, and to impose strain on connection points within the assembly. These problems are alleviated to a considerable extent by the provision of a swivel capability (rotation about the longitudinal axis of the connection port) at the patient interface. Unfortunately, the provision of such a capability has heretofore involved the incorporation of swivel elements which are inordinately expensive and/or which provide an unreliable seal for the system.
Material prior art structures and methods are described, among other places, in U.S. Pat. No. 4,569,344 to Palmer. The ""344 patent illustrates an aspirating/ventilating system of the type referred to in this disclosure. The illustrated system typifies the problem addressed by the present invention.
There remains a need for an inexpensive, yet reliable, connection structure capable of providing a sealed passageway through a rotating or swiveling joint.
The present invention provides an improved swivel connection apparatus which is generally useful for providing a gas-tight passageway between the interiors of discrete components of a fluid delivery system. The apparatus is structured and arranged to permit connection between tubular elements or conduits associated with such components. It is uniquely useful for connecting tubular elements of medical apparatus and the like. Accordingly, it is described in this disclosure with particular reference to one such application; endotracheal ventilating and aspirating assemblies. It is not thereby intended to suggest that the applicability of this improvement is limited to the medical field or to the scale appropriate for medical intubation devices. The connector of this invention is generally useful in connection with low pressure systems requiring an inexpensive joint connection. While the invention may be embodied in robust versions suitable for use in high pressure and/or large scale applications, alternative structures are available for such applications, and the benefits of this invention are correspondingly less apparent.
The invention may be embodied as an element of a manifold, typically a multi-functional manifold positioned at the distal end of a catheter assembly. A catheter tube is slidable lengthwise through a passageway between proximal and distal sides of the manifold. The manifold preferably includes a conduit at its distal side for attachment to (and communication with) an indwelling intubation device, such as a tracheal tube, endotracheal tube or nasopharyngeal tube. The manifold also preferably includes a ventilating structure extending radially from (and in fluid communication with) the passageway. The ventilating structure constitutes means for selectively introducing ambient air, oxygenated air and other therapeutic gases into the respiratory system of the patient. Other conduits may also be provided for the introduction of therapeutic and diagnostic implements and for the introduction of other suitable gases and lavage solutions to the respiratory system.
The manifold may be structured and arranged to enable simultaneous patient ventilation and protected tracheal suctioning. A suctioning catheter may be coupled at its proximal end to a suctioning valve. The distal end of the catheter may then be fed through a conduit at the proximal side of the manifold for reciprocal movement through the intubation device. The catheter is often provided in an assembly, whereby it is enveloped by a sterility-enhancing protective barrier, which is coupled to the proximal side of the manifold.
In use, the manifold assembly is interposed between an indwelling tube at the distal end of the manifold and a ventilating circuit. These junctions preferably embody a swivel configuration to permit left or right bedside placement of the ventilation circuitry, and free rotation of the ventilation circuit with patient head movement to reduce the risk of extubation. The present invention provides a particularly advantageous such connection.
The connector of this invention comprises a pair of cooperating parts. The first such part typically comprises a structural element carried by a system component, such as the manifold of an endotracheal ventilation system. This structural element may take a variety of forms, but in any case presents an approximately cylindrical interior surface, constituting the female portion of the connector.
The second part of the connector usually has a hollow interior between first and second open ends. Each such end is structured and arranged to couple with respective discrete system components. The first open end of the second part constitutes the male portion of the connector. It includes an outer surface configured to register, in sliding seal relation, with the female portion of the connector. This outer surface is thus approximately cylindrical, and is sized appropriately for insertion within the female portion. The distal end segment of the hollow cylinder (the male portion) is flared to an enlarged diameter so that it effects a self-biased engagement with the interior surface of the female portion across a relatively small surface area. In this fashion, an effective gas seal is maintained by the natural hoop strength of the flared end, with only a minor amount of frictional resistance against rotation of the male portion of the connector within the female portion of the connector. The flared segment is usually of reduced wall thickness and somewhat more flexible than the remainder of the male portion. The seal created by mating of the female and male portions is effective when the pressure within the hollow center of the connector is either positive or negative with respect to ambient conditions, within the practical range normally encountered in medical applications.
The second open end of the second part of the connector is structured and arranged for coupling to a second system component. For example, a tube may be press fit into an entry port opening into the second end to effect a mechanical connection. Rotation of the tube then effects equivalent rotation of the male portion within the female portion of the connector, thereby avoiding strain in the joint between the system components. A terminal segment of the second end may further be structured cooperatively to form a journal bearing connection with structure associated with the first part of the connector. In this fashion, the first and second parts are supported against radial displacement or twist, which could interfere with smooth rotational displacement of these parts with respect to each other.
An alternative embodiment substitutes, or includes as an interchangeable element, a second part with a closure of the hollow interior. This closure may be at the first end or otherwise constitute an occlusion of the open interior spaced from the flared distal end. This modification may serve as a plug in appropriate circumstances.
Thus, according to this invention, a connector for openly connecting conduits includes approximately cylindrical male and female parts adapted to couple ideally by a plug fit, (such as a snap fit or press fit) connection, and those parts are structured to permit relative rotational displacement while they are in coupled condition. One part, usually, the female part, may be constructed of any rigid material. The other, usually the male part, is constructed of material having sufficient resiliency and flexibility to provide a self-biased seal against a portion of the interior surface of the more rigid part. Medical grade plastics are generally satisfactory for this purpose.
According to certain preferred embodiments, the male portion of the apparatus of this invention comprises an outer surface configured to register, in sliding seal relation, with the female portion and includes a distal end segment of enlarged diameter such that it effects a self-biased engagement with the interior surface of the female portion across an annular band of relatively small surface area. The male portion generally comprises an approximately cylindrical annulus having reduced thickness at the distal end segment. The opposite, or proximal end of the male portion and the connection end of the female portion may be cooperatively structured to form a journal bearing arrangement. The journal bearing arrangement is constructed by coupling these complementary ends in plug fit engagement, whereby to resist axial displacement of male and female portions with respect to each other.
More specifically, apparatus for openly connecting a first conduit element to a second conduit element includes complimentary female and male portions. The female portion comprises an approximately cylindrical inner surface structured for association with the first conduit element. The inner surface has a first sealing region and the female portion carries a first coupling element. The apparatus further includes a male portion comprising an approximately cylindrical outer surface structured for association with the second conduit element. The outer surface has a second sealing region in registration with the first sealing region and the male portion carries a second coupling element in registration with the first coupling element. The first and second coupling elements are constructed and arranged to effect a journal bearing connection, and the first and second sealing regions are structured to permit low friction rotation while maintaining a fluid tight seal at the interface between the inner and outer surfaces.